Author contributions
Z.C.X., Y.Z.X. and C.X.M conceived and designed the study. Z.C.X., Y.Z.X and W.H.Y. collected samples. W.H.Y. and Y.Y.X. performed the genome assembly, gene model prediction, gene annotation and comparative analyses. H.H.J. performed the chromosome analyses. W.H.Y., Y.Z.X. performed the transcriptome analyses. W.H.Y., Y.Z.X. and Y.Y.X. wrote the manuscript with input from all authors. Z.C.X., Y.Z.X. and C.M.S. analyzed the data and discussed the results. All authors reviewed the manuscript.